The present invention is generally related to medical devices, kits, and methods. More specifically, the present invention provides a system for accessing stenosis, partial occlusions, or total occlusions in a patient""s body.
Cardiovascular disease frequently arises from the accumulation of atheromatous material on the inner walls of vascular lumens, particularly arterial lumens of the coronary and other vasculature, resulting in a condition known as atherosclerosis. Atheromatous and other vascular deposits restrict blood flow and can cause ischemia which, in acute cases, can result in myocardial infarction or a heart attack. Atheromatous deposits can have widely varying properties, with some deposits being relatively soft and others being fibrous and/or calcified. In the latter case, the deposits are frequently referred to as plaque. Atherosclerosis occurs naturally as a result of aging, but may also be aggravated by factors such as diet, hypertension, heredity, vascular injury, and the like.
Atherosclerosis can be treated in a variety of ways, including drugs, bypass surgery, and a variety of catheter-based approaches which rely on intravascular widening or removal of the atheromatous or other material occluding the blood vessel. Particular catheter-based interventions include angioplasty, atherectomy, laser ablation, stenting, and the like. For the most part, the catheters used for these interventions must be introduced over a guidewire, and the guidewire must be placed across the lesion prior to catheter placement. Initial guidewire placement, however, can be difficult or impossible in tortuous regions of the vasculature. Moreover, it can be equally difficult if the lesion is total or near total, i.e. the lesion occludes the blood vessel lumen to such an extent that the guidewire cannot be advanced across.
For these reasons, it is desired to provide devices, kits, and methods which can access small, tortuous regions of the vasculature. In particular, it is desired to provide systems which can access partial occlusions, total occlusions, stenosis, blood clots, or thrombotic material. At least some of these objectives will be met by the devices and methods of the present invention described hereinafter and in the claims.
The present invention provides a hollow guidewire working channel system. The system optionally includes a deflectable distal tip that can allow the hollow guidewire working channel to be steered through the body lumen. The guidewire system of the present invention typically includes an elongate body comprising a proximal end and a distal end. A deflectable distal tip can be coupled to the distal end of the elongate body. The guidewire system optionally includes at least one pull wire that can extend through the elongate body to couple to the distal tip. The pull wire is offset from a longitudinal axis of the distal tip and elongate body, such that axial manipulation of the pull wire deflects the distal tip in a desired direction. By torquing or twisting a proximal end of the hollow guidewire working channel, the deflected tip can be steered and advanced through the tortuous regions of the vasculature.
The hollow guidewire system can be used as a support or access system an can be navigated to and positioned at the target site, with or without the use of a separate guidewire. The hollow guidewire provides the flexibility, maneuverability, torqueability (usually 1:1), and columnar strength necessary for accurately advancing through the tortuous vasculature either over a standard guidewire or on its own. The hollow guidewire working channel has superior strength and rigidity characteristics that are not found in conventional balloon angioplasty or infusion catheters. The hollow guidewire system provides superior physical support for other interventional devices inserted within its lumen as compared to polymeric catheter devices. The hollow guidewire system allows the support of devices used for the dottering (i.e., trying to poke through) of occlusions or stenoses while retaining the desirable characteristics of flexibility, trackability, and torqueability.
The hollow guidewire system can act as a working channel inside of which other interventional devices can be delivered to the target site, such as a rotating guidewire or drive shaft, infusion guidewire, clot maceration guidewire, normal guidewires of varying stiffness, and the like.
Many thin walled polymeric based catheters do not have sufficient maneuverability or torqueability to be advanced through tortuous body lumens on their own and must be navigated to an occlusion over a standard guidewire. In order for these polymeric catheters to be used as working channels, to physically support devices inserted within the catheter lumen intended to penetrate or otherwise treat such lesions, the wall thickness must be increased, which results in a reduction of the size of the inner lumen. In contrast, the hollow guidewire working channel of the present invention typically has a thin wall construction while still providing sufficient torqueability and maneuverability to be advanced through the body lumen, either over a standard guidewire or on its own. Consequently, the thin coil walls allows the lumen of the working channel to be maximized. This allows larger diameter devices to be inserted into the lumen than can be inserted into conventional polymeric based catheters. The larger lumen of the hollow guidewire working channel allows devices such as clot macerators and other larger devices to be delivered to the target lesion. Additionally, the larger diameter lumen of the hollow guidewire allows for infusion of clot dissolving or other fluids, and for aspiration of debris stirred up in the clot maceration process.
Unlike conventional infusion and catheter devices, the hollow guidewire working channel can have a tip which has the same diameter as the rest of the elongate body. Additionally, a radio-opaque marker can be positioned on the extreme distal tip of the catheter. This allows the user to precisely identify the position of the distal tip of the device. Identification of the precise location of the extreme distal tip is advantageous as it allows devices inserted into the working channel to be positioned precisely at the front surface of the occlusion or stenosis.
In some embodiments, the distal tip will optionally have ribs or slots to facilitate deflection in the desired direction. The ribs can be even or tapered.
In use, the hollow guidewire can be advanced through the vasculature to the lesion. Flexing or deflecting the distal tip controls the position and orientation of the devices disposed within the lumen and can avoid perforating the body lumen wall. For example, if the hollow guidewire is navigated to the lesion and the distal tip of the hollow guidewire system is pointed in a direction toward the vessel wall, the direction of the distal tip can be changed by deflecting the tip and torquing and twisting the proximal end of the hollow guidewire system.
These and other aspects of the invention will be further evident from the attached drawings and description of the embodiments of the invention.